The invention relates to a transformer shielded with a short ring, and more particularly to suppression of electrostatic interference from a transformer with a short ring by electrical connection of the short ring to a predetermined potential through a discharge path.
When a transformer is used in an electronic circuit or system, it is known to reduce or eliminate leakage flux from the transformer by use of a short ring. In this regard, a short ring is a closed, annular ring of electrically conductive material (or soft magnetic material) that girds the transformer, on the outside of the transformer's windings and core. The purpose of the short ring is to shield nearby components from magnetic flux that leaks from the transformer's windings and core. For example, in a color television (CTV) system, use of a short ring in a switching power supply can reduce or eliminate 60 Hz "hum" from the audio and video portions of TV programming.
While a short ring can effectively suppress or eliminate electromagnetic interference, its structure and operation, and/or the structure and operation of a transformer shielded by the short ring, can produce an electrical potential that may capacitatively discharge to adjacent components, causing electrostatic disruption of the components.